this happens when there are field marks in both the middle field and one or more in the left or right fields in which case the marks only display for the middle field. this was not intended of course but presents a problem in how to display all of them. i'm suggesting to the programmer at this point to use a goal-post type of symbol so that all the symbols can display properly.
unfortunately october is going to be a sleepy month for new features as my programmer is tied up in other projects excepting emergency bugs. look for this and other enhancements to come starting in november.